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    <title>Document</title>
    <script src="./函数2次封装.js"></script>
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    <script>
            call 会执行函数，并且能改变this指向
        // function foo(){
        //     console.log(this); 
        // }

        // function hello(){
        //     const that={
        //         hello:'hello'
        //     }
        //     foo.call(that)
        // }

        // console.log(foo());
        // console.log(hello())

        function foo(a,b,c){
            console.log(this,a,b,c); 
        }

        function hello(){
            const that={
                hello:'hello'
            }
            call(foo,that,1,2,3)
        }

        foo()
        hello()
    </script>
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